The U.S. Coast Guard crews sent to rescue them are now wondering where they all went.

After two days of search-and-rescue missions by helicopter, the crews say they have seen relatively few people in need of assistance and have spotted no corpses in the debris-clogged waters that have inundated the island.

"I'm looking around and wondering where all those people are," Coast Guard flight mechanic Jason Carty said Sunday, describing a midday helicopter flight along the length of the island. He saw considerable destruction but no people seeking rescue.

There have been numerous dramatic rescues, with crews risking their lives to save people from onrushing waters and from flooded houses. Crews described plucking terrified people, including children, from vehicles and homes. But they also said they expected to see more residents in distress given the magnitude of the storm and the number of people believed to have remained on the island.

That raises the question of whether those who did stay are now surviving at home without electricity or running water, or whether some did not survive and have not yet been found.

Lt. Matt Gully, a helicopter pilot, said he flew over the Galveston Bay side of the island and saw flooded homes and marooned livestock, but no people.

"It was very surprising, but there was no one in need of assistance," Gully said.

State authorities say 1,984 people have been rescued along the Texas Gulf Coast since Ike slammed ashore Saturday morning -- 394 of them by air -- but they have no estimate for those rescued from Galveston alone. In Louisiana, 393 have been rescued.

In Texas, search-and-rescue air operations have been mounted by the Coast Guard and the Texas Army and Air Force National Guard. There are 1,500 rescuers and 57 aircraft, said Lt. Col. Shaunte Cooper of the Air Force National Guard.

Some 2,000 Galveston residents who braved the storm in their homes agreed Sunday to an offer by city officials to be bused to shelters in San Antonio and Austin.

Rescue crews were mounting a door-to-door search of homes in Galveston and other coastal towns, local officials said Sunday.

"There is not a square foot that will not be searched," Galveston City Manager Steven LeBlanc said.

LeBlanc said he was most concerned about those who stayed through the storm on the island's west end, which was battered by a surge and waves.

"There were people out there," he said. "What happened to them, I don't know."

LeBlanc said he has spotted cattle, but "that's the only life I saw on the west end."

Flying over the main part of the island Saturday after the storm struck, Petty Officer Matt Russell said he saw no one in need of assistance.

"I didn't see anyone trapped in the water," Russell said.

He said he saw people sloshing through water to remove debris from their yards or wading to neighbors' houses.

Some waved at his helicopter, he said, and others ignored it.

"We hovered to see if anyone was in distress, but no one indicated they needed any help," Russell said.

Flying for 14 hours over two days, Russell said, his crew rescued at least 20 people, many of them from the hard-hit Bolivar Peninsula northeast of Galveston.

Russell and other crew members described the devastation on Bolivar as even worse than what they witnessed on Galveston Island.

"A lot of houses that were there aren't there now," the Coast Guard's Carty said.

Most of the houses on Bolivar are built on stilts, rescue swimmer Shane Moore said, "but all you see now are the stilts. The houses are just gone."

Russell and Moore described rescuing four men and three children Friday from a pickup on Bolivar. They said the truck was being dragged out to sea by a tidal surge preceding Ike's landfall.

Moore, 23, said he got into the surf to reach the truck. "I didn't realize how powerful the surf was -- it crashed over my head," he said. At one point, the surf knocked him out of the truck bed.

Moore said he was able to strap all seven people, one at a time, to him as he was hoisted into the helicopter. All seven were rescued with no serious injuries, he said.

"They were pretty panicked," Moore said. "They were beat up by the surf, really in serious trouble."

Russell said he asked one of the men why he stayed in the face of the hurricane.

"He told me: 'I thought I had more time,' " Russell said.

Russell, 24, took a few hours off Sunday to check on his apartment in Bayou Vista on the Texas coast. Floodwaters had crashed through the lower floor, ravaging everything inside, he said.

He had taken his most valuable possessions before the hurricane and moved in with a friend inland. But the experience made him wonder why anyone would try to face down a hurricane.

He said he rescued one couple who survived the storm inside their house, but were marooned by floodwaters.